In recent years, color organic EL displays with a driving method using thin film transistors (TFTs) have been developed. With a method in which the light is extracted from the side of the substrate on which the TFTs are formed, due to the effect of wiring parts blocking the light, the aperture ratio cannot be raised; recently, a so-called top emission method in which the light is extracted from the opposite side to the substrate on which the TFTs are formed has thus been developed.
On the other hand, there have been advances in development of a color conversion method in which patterned fluorescent bodies are made to absorb light emitted from an organic EL device and hence fluorescence of a plurality of colors is emitted from the fluorescent bodies. By using this method together with the top emission method using TFT driving, there is the possibility of being able to provide an organic EL display having yet higher definition and higher brightness. The color displays disclosed in Japanese Patent Application Laid-open No. 11-251059 and Japanese Patent Application Laid-open No. 2000-77191 are examples of such a system.
As a structure of a top emission display using the color conversion method, in Japanese Patent Application Laid-open No. 11-297477 there is disclosed a structure in which an organic EL device and color-converting filters (color-converting layers alone or laminates of color filter layers and color-converting layers) are disposed facing a transparent electrode on the upper side of the organic EL device with a fixed gap provided therebetween by a columnar gap-adjusting layer disposed therebetween. Moreover, a structure in which this gap is filled with an insulating oil or the like is disclosed in Japanese Patent Application Laid-open No. 3-92398.
However, with the constitution in which a fixed gap is provided using a columnar structure (support), there is a gas layer (void) having a greatly different refractive index between the organic EL layer and the color-converting filters, and hence there is much reflection of light at the interface between the gas layer and the organic EL device, and at the interface between the gas layer and the color-converting filters, and thus the efficiency of extracting light is reduced. Moreover, with the constitution in which the gap is filled with an insulating oil or the like, this problem of reflection is alleviated, but the display manufacturing process becomes more complicated, and moreover the shock resistance, which is an intrinsic advantage of an organic EL display that is a completely solid device, is marred, and hence this constitution cannot be said to be the best.
As a constitution resolving these problems, in Japanese Patent No. 2766095 there is disclosed a constitution in which an organic EL device, and color-converting filters that face a transparent electrode on an upper part of the organic EL device are firmly bonded together via a transparent resin layer. However, with this constitution, there is a problem of damage such as peeling away of the EL device occurring through mechanical stress such as vibration or pressure or thermal stress produced, for example, through changes in the temperature of the environment in which the manufactured display is placed or during the step of bonding the organic EL device and the color-converting filters together.
Furthermore, in Japanese Patent Application Laid-open No. 11-121164, there is disclosed a constitution in which a base film, which is a resin film, and a binding layer, which is also a resin film, are formed between an organic EL device and color-converting filters with the binding layer on the color-converting filter side. In Japanese Patent Application Laid-open No. 11-121164, it is stated that the roles of the binding layer are to flatten out level differences on the color-converting filters, and to function as a cushioning film between the color-converting filters and the base film. However, in Japanese Patent Application Laid-open No. 11-121164, no consideration is given to adjusting the gap between the color-converting filters and the organic EL device. Moreover, the binding layer is made to function merely as a cushioning film with the base film, and there are no suggestions regarding relieving stress on the crucial organic EL device. Furthermore, the invention of Japanese Patent Application Laid-open No. 11-121164 does not have TFTs, and hence there is no mention of resolving problems peculiar to an organic EL display having TFTs as in the invention.